Brown azo dye.



belongs.

UNITED STATES PATENT QFFICE.

MARTIN HERZBERG AND FRIEDRICH RUNKEL, OF ELBERFELD, GERMANY, ASSIGNORS TO FARBENFABRIKEN VORM. ERIEDR. A. CORPORATION OF GERMANY.

BAYER & C0,, OF ELBERFELD, GERMANY,

BROWN AZO DYE.

No Drawing.

Specification of Letters Patent.

Application filed August 17, 1909.

Patented Mar. 29, 1910.

Serial No. 513,336.

To all whom 'it may concern:

Be it known that we, MARTIN I'IERZBERG' and FRIEDRICH RUNKEL, doctors of philosophy, chemists, citizens of the German Empire, residing at Elberfeld, Germany, have invented new and useful Improvements in Brown Azo Dyes, of which the following is a specification.

This application relates to the manufacture and production of a specific new azo dye which can be obtained by combining in alkaline solution the diazo compound of ortho-aminophenylether sulfonic acid with I Q" 2 phenylamino 8 naphthol 6 sulfonic acid,

while in a previous application Serial No. 512,891, filed August 14th 1909 we described the whole class to which this specific dye The new dyestuff is after being dried and pulverized in the shape of its sodium salt a dark powder soluble in water with a reddish-brown color and soluble in concentrated sulfuric acid with a blue-red color.

I Upon reduction with stannous chlorid and weight: 26.5 {ether sulfonic acid are dissolved in hot hydrochloric acid it is decomposed orthoaminophenylether sulfonic acid and 7- a1nino-2-pheny1amino-8-naphthol- 6 sulfonic acid is obtained.

The new coloring matter dyes wool from acid baths brown shades remarkable for their fastness to washing and to milling.

In order to carry out our process We can 6. g. proceed as follows, the parts being by parts of ortho-aminophenylwater with the addition of 6 parts of anhy- 1 drous sodium carbonate. 7 parts of sodium nitrite are added and the mixture is introduced into cold water containing parts of crude hydrochloric acid. The diazo compound is introduced into a cold aqueous solution of 31.5 arts of 2-phenylam1no-8- naphtho1-6-sulfon1c acid containing an excess of sodium carbonate. The dyestuff which precipitates is filtered off, washed and dried.

To claim: I

The herein described new azo dyestufi obtainable from diazotized ortho-aminophenylether sulfonic acid and 2-phenylamino 8- naphthol-G-sulfonic acid, which dye is after being dried and pulverized in the sha e of its sodium salt a dark powder solube in water with a reddish-brown color and soluble in concentrated sulfuric acid with a bluered color; yielding upon reduction with stannous chlorid and hydrochloric acid ortho-aminophenylether sulfonic acid and 7 -amino-2-phenylamino-8 naphthol 6 sulfonic acid; and dyeing wool brown shades remarkable for their fastness to washing and to milling, substantially as described.

In testimony whereof We have hereunto set our hands in the presence of two;sub-

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